This invention relates to swivel locking devices, and particularly to a swivel locking device of improved construction and reliability.
It is often desirable to secure an animal or some other movable object in a particular area while still allowing for some freedom of movement for the animal or other object. For example, it is desirable in the case of an animal such as a dog to allow the dog freedom to move, but at the same time prevent the dog from straying out of a local area. To accomplish this, a length of leather, rope, or preferably a metal chain, (hereinafter collectively referred to as the "chain") is attached at one end to a collar on the neck of the dog, and at the other end is attached to a fixed object, such as a tethering stake in the ground, or a wire run arranged between two fixed objects, such as trees.
In order to facilitate attaching and detaching the animal using such an arrangement, conventionally one or both ends of the length of chain are provided with some type of readily attachable securing device, such as a spring-loaded link, in which a spring present in the link acts to close the link and thereby secure one end of the leash comprising a loop, e.g., the terminal link of a chain. An example of a snap link of this type is described in U.S. Pat. No. 3,911,671.
Because an animal secured as noted above may also move in circular patterns or repeatedly turn in a particular direction, it is also desirable to provide a swivel mechanism in the chain between the dog and the fixed object, so that the chain does not become coiled and tangled. This can be accomplished by use of a snap swivel.
Spring-loaded snap links and swivels are subject to failure due to loss of resiliency of the spring, rusting of the spring mechanism resulting in sticking, and are relatively expensive to manufacture with the precision required for proper utility. A loss of resiliency of the spring can easily result in opening of the link when subjected to stress, such as by the movement of an animal such as a dog.
Therefore a need exists for a simple, inexpensive, reliable means for securing an animal or other object to a fixed object.